On this day, in 1866, the 14th Amendment to the United States Constitution was finally certified by Secretary of State William H. Seward. The amendment guarantees that no state “shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law.”

The 14th amendment has become one of the most important elements of American Constitutional law and certainly one the most contentious. It was in many ways the result of a half-century debate about rights in the antebellum period, a product of Union victory in the Civil War, and the triumph of the newly-formed Republican Party led by Abraham Lincoln.

Lincoln believed that through his political philosophy and his actions as a leader he was channeling the Founding Fathers, even as he was ultimately changing the republic that he inherited from them. In many ways, the 14th amendment is in tension with the principles of federalism, and many believe that an expansive view of its power to protect “rights” will ultimately lead to every policy and decision flowing through the Federal Government. Yet others see it as a vital safeguard for individual rights, including the economic rights largely ignored by the Supreme Court in the 20th century.

Regardless of the varying interpretations of the 14th Amendment, the Civil War set a definite course for the future United States: secession was buried as a legal principle, slavery was abolished, and the idea that “all men are created equal” with “certain unalienable rights” was placed at the cornerstone of American institutions. To understand the debate over principles in our own era in relation to the Fathers, we must go through Lincoln.

Historian Richard Brookhiser’s insightful book on Abraham Lincoln, Founder’s Son: A Life of Abraham Lincoln, elucidates the connection between Lincoln’s ideas and those of the Founders. Brookhiser has spent years writing biographies and histories of the time in which the Founding Fathers lived, bringing key insights into the the principles and passions that motivated that generation. Brookhiser’s new book on Lincoln is uniquein that, as he himself notes, “a historian of the founding looks ahead to Lincoln.”

Brookhiser explains how Lincoln grappled with the founders’ ideas and became their most fervent advocate. The Great Emancipator came to admire some Founders, such as George Washington, for fighting and suffering for liberty. Others, like Thomas Jefferson, profoundly disappointed Lincoln because of their failures in personally addressing or making an effort to end the institution of human bondage. Yet Lincoln believed he was carrying on the tradition of the Founders in opposition to a rising pro-slavery philosophy. In Lincoln’s mind, these ideas would corrupt the republic, leading to its utter and irrevocable transformation.

Brookhiser explains the ideas arrayed against Lincoln, best articulated by Lincoln’s friend and former political ally Alexander H. Stephens, the first and only Vice President of the Confederacy.

In his famous “Cornerstone” speech, Stephens explained how the Confederate Constitution would ultimately be created in opposition to the Founders, in particular to Jefferson’s notion in the Declaration of Independence that “all men are created equal.”

Stephens said:

Our new government is founded upon exactly the opposite idea; its foundations are laid, its corner- stone rests, upon the great truth that the negro is not equal to the white man; that slavery subordination to the superior race is his natural and normal condition. This, our new government, is the first, in the history of the world, based upon this great physical, philosophical, and moral truth.

Founder’s Son is not a colorless history tome, bogged down in detail and trivial fact, but rather a perceptive look into the mind and world of America’s 16th president. This is Brookhiser’s genius as a writer, and what makes his books a joy to read; few can so clearly and accurately describe such a complex subject and the substance of what made him worthy of being studied and respected.

The following is Brookhiser’s interview with Breitbart News, explaining some of the most important elements of his book: how Lincoln’s ideas shaped American history, and what they mean for Americans today who also wish to preserve the tradition passed down by the Fathers.

Breitbart News: This week is the anniversary of William H. Seward certifying the ratification of the 14th Amendment. Although crafted by John Bingham and enacted after his death, what do you believe Lincoln would have thought about this amendment which has had so much impact on American jurisprudence?

Richard Brookhiser: In his last speech, April 11 1865, Lincoln hoped that “the colored man” would be inspired “with vigilance, and energy, and daring” to win civil rights in post-war southern state governments. (It was this sentence that caused John Wilkes Booth, who was in the audience, to say “That means nigger citizenship. That is the last speech he will ever make.”) If it needed the 14th and 15th amendments to make citizenship for the freedman happen, so be it. Lincoln would have used all his arts–humor, poetry, patience, politics–to try to smooth the process.

Breitbart News: Abraham Lincoln had been a Whig for most of his adult life, surrounded by Democrats and those who politically opposed him in Illinois. The Whigs—once led by Lincoln’s “beau ideal of a statesman” and notable, masterful compromiser Henry Clay—sputtered and died in the 1850s. Its voters fled to greener pastures. Lincoln made a jump to the newly-formed and more staunchly anti-slavery Republican Party, which dominated for nearly half a century. However, the country went through by far its worst period of bloodshed. Some historians believe that a failure to compromise led to war, yet others like Seward believe it was an “irrepressible conflict.” Was the Civil War preventable, and more importantly, would its prevention have been a good thing?

Richard Brookhiser: The Civil War need not have happened if a majority in the free states could have accepted, in the short run, slavery in Kansas and an American purchase or conquest of Cuba; in the long run, America as a beacon for racial slavery in the world.

Lincoln admired Henry Clay because for all his compromising, he loved liberty, he believed America was founded on it, and he believed that men were entitled to it by nature. Lincoln’s favorite Clay quotation ends this way: “[You] must penetrate the human soul, and eradicate the light of reason, and the love of liberty. Then, and not till then…can you perpetuate slavery.”

Breitbart News: Your thesis mostly revolves around the link between Abraham Lincoln and the Founding Fathers. While Lincoln felt he had little connection to his own father, you make a convincing argument that the Founders became a kind of surrogate for the Great Emancipator. They drove his thoughts about philosophy and his actions in politics. Reviving the principles of the founders became a “new birth of freedom” for America and led to the accomplishment of something that great generation never did in completely eradicating slavery.

Do Americans still have a deep connection to the America that the Founders created and the principles they passed down to us? Do we still resemble the people de Tocqueville described in Democracy in America?

Richard Brookhiser: The biggest hit on Broadway right now is a hip-hop musical about Alexander Hamilton. In 1969 (the year of Hair) it was a musical about John Adams and the Declaration of Independence. The appetite is there, the potential for affection and understanding is there. I’m a glass half full guy, I’ll take that. My job is to tell the stories, other people have other jobs. Don’t stop, never quit. That’s how the founders did it. If we want to be like them, we have to behave like them.

Breitbart News: You frequently mention Edward Everett, and old Whig who delivered the first, hour long speech that preceded Lincoln’s Gettysburg Address. His famous oration on “The Character of George Washington” was exceedingly popular in the 1850s, but you seem to have been critical of it. He preached of Washington’s ability to bring “unity” to the nation, but unity without much content. You wrote that, as opposed to Everett’s Washington, “Lincoln’s Washington fought for liberty.”

Given the importance of founding principles and attachment to liberty, what is the best way for modern Americans to get in touch with the Founders?

Richard Brookhiser: Empty piety can be as bad as snark or ignorance. So: read, think, act. What more is there?

Follow Jarrett Stepman on Twitter:@JarrettStepman. Reach him directly at jstepman@breitbart.com.